This disclosure relates to an integrated drive generator for aerospace applications, for example. More particularly, the disclosure relates to a pump plate for a hydraulic unit of the integrated drive generator.
One example type of integrated drive generator (IDG) includes a generator, a hydraulic unit and a differential assembly arranged in a common housing. The differential assembly is operatively coupled to a gas turbine engine via an input shaft. The rotational speed of the input shaft varies during the operation of the gas turbine engine. The hydraulic unit cooperates with the differential assembly to provide a constant speed to the generator throughout engine operation.
The hydraulic unit includes a pump plate that separates variable and fixed pumping assemblies. The pumping assemblies communicate fluid between first and second passages in the pump plate to vary the rotational output of the hydraulic unit and provide the constant speed. One example pump plate provides a flow rate of 0.35 in3/rev with the first and second passages having volumes of 0.150 in3 (2.46 cm3) and 0.161 in3 (2.64 cm3), providing flow rate to volume ratios of 2.33 and 2.17. The first and second passages include webbing reinforcements, which have a volume ratio compared to the open area of 9.7% to 17.2%. The pump plate is constructed of cast ductile iron and has a thickness of 0.625 inch (1.59 cm). The ratio of flow rate to webbing volume is 10. For a higher output IDG, the pump plate permits inadequate flow through the passages and may be too weak.